Armstead signed with the Patriots from the Canadian Football League last year. He eventually was placed on the reserve/non-football injury list after undergoing a procedure to treat an infection. Armstead also suffered a heart attack in college at USC and has a pending lawsuit in regards to painkillers he was given in college that led to it.

“It has been a pleasure being around Armond, as he gave everything he could to play for us,” Patriots coach Bill Belichick said in a statement released by the team. “Armond worked extremely hard since joining us last February.

“He’s had a lot of adversity personally that he’s had to deal with — unusual compared to most other players — but he’s always had a great attitude, worked hard and really did everything we asked him to do. While it is unfortunate he will not be able to play football, Armond is an outstanding young man who has a very bright future in whatever path he chooses.”

Armstead played one season for the CFL’s Toronto Argonauts and helped them win the 2012 Grey Cup. He was a CFL All-Star with 43 tackles and six sacks.